Low profile floor conveyor



Aug. 9, 1966 A. CZARNECKI LOW PROFILE FLOOR CONVEYOR 5 Sheets-Sheet 1 Filed March 24, 1964 7; j] if f! 0 M )1 ms gw Aug. 9, 1966 A. CZARNECKI LOW PROFILE FLOOR CONVEYOR 3 Sheets-Sheet 2 Filed March 24. 1964 Aug. 9, 1966 CZARNECKI 3,265,013

LOW PROFILE FLOOR CONVEYOR Filed March 24, 1964 3 Sheets-Sheet 3 I l K 1. I I I I I I 1| 1| l l W I II I zd/ /Z fdfficdjz United States Patent 3,265,013 LOW PROFILE FLOOR CONVEYOR Adolph Czarnecki, Birmingham, Mich, assignor to Anchor Steel & Conveyor Company, Dearborn, Mich, a corporation of Michigan Filed Mar. 24, 1964, Ser. No. 354,365 19 Claims. (Cl. 104-432) This invention relates generally to conveyor systems and more specifically to conveyor systems which are adapted to be mounted on the concrete subfioor of a factory building.

When installing a subfloor conveyor system in an existing factory building of a conventional type having a concrete slab fioor overlayed by two-inch wood blocks, it has been necessary heretofore to strip away the wooden blocks along the path of the proposed conveyor, then break up the concrete subfloor to provide a trench of sufiicient depth to accommodate the conveyor and finally, after the conveyor has been installed, to pour concrete and to replace the wood overlay alongside the conveyor. Manifestly, this operation is tedious, difficult, time-consuming and costly, and it involves much dust and noise that interferes with continuous operation of the factory during the installation. Further, with manufacturing procedures in a constant state of flux and retooling for new products occurring frequently, a manufacturer may desire to change the conveyor system already in existence in the plant. In this situation, the old system must be removed, the trench repoured with concrete and the wooden blocks replaced. Then the process for installing a new system described above must be utilized, with its accompanying problems.

Thus, a need exists for a conveyor system that may be installed in existing buildings or new buildings and which may be installed without the attendant breaking up of the concrete floor and repouring thereof described above. The system of the present invention fills this need in that the improved system has an overall height of approximately two inches, to enable it to be installed directly on the uniplanar concrete subfloor in the space left by the removed wooden blocks. The use of air hammers and repouring of concrete has been substantially eliminated in the system of the instant invention, it being only necessary to strip the wooden blocks away'and install bolts into the concrete subfloor to anchor the system.

Also a need has developed for a conveyor system wherein the drive-chain slot is effectively closed at the top thereof to preclude foreign matter from dropping into the slot where the drive chain is located. In the past, the conveyor systems have had chain slots which were substantially open to receive any material which may drop therein. Thus, dirt, grease and the like would accumulate in the slot to cause greater wear of parts and slow down, even to the point of stopping, the operation of the chain. As is readily apparent, the more open the slot the greater the maintenance costs to keep the slot free of material which may cause malfunctioning or stoppages. The conveyor system of the instant invention provides a vertically closed slot to substantially eliminate the possibility of extraneous material dropping into the drive-chain slot.'

Further, in many systems of the prior artthe conveyor chain presents an irregular upper surface to the tow pin of a truck which must be engaged thereby. Thus, the tow pin must either be accurately positioned in the pin-engaging member of the conveyor chain or the pin may be placed on the chain and allowed to bump along on the upper surface thereof until the pin isin position to engage the chain. There are certain problems involved insuch a system which should be alleviated. For example, undue Wear of the chain may occur, the pin may bounce over the pin-engaging member, etc. Thus, the invention contem- 3,265,13 Patented August 9, 1956 "ice plates providing an assembly of chain linkages that allows the draw pins of a vehicle to be dropped anywhere in the slot of the conveyor chain. The chain is so constructed that the draw pin will freely ride the top of the chain until the pin can drop into the proper place in the chain.

Also, in certain prior art systems, a complex transfer mechanism is provided to permit the operator to direct the tow truck onto predetermined branch tracks as is necessary in systems of this type. These prior art systems often involve complex pneumatic and gear systems which are difficult to maintain and expensive to repair. While these prior art systems have been satisfactory in the past, a need has developed for a more simple, inexpensive transfer mechanism.

In this regard, the invention contemplates providing a novel system of pockets and camming surfaces to effectuate a smooth and reliable transfer of the vehicle onto a side track. With the system of the instant invention, it is only necessary to program the vehicles as they leave the starting point to insure a reliable and trouble-free predetermined path through the system. Further, the mechanism provided at the transfer point involves merely changing the profile of the slot and providing indexing surfaces, thus eliminating the complex transfer mechanisms heretofore known in the art.

Accordingly, it is an object of the present invention to provide an improved conveyor system.

Another object of the present invention is to provide a conveyor, system that is simple and inexpensive to install over systems heretofore known.

Another object of the present invention is to provide a conveyor system that may be installed in a space of minimal height such as that provided by the removal of the wooden blocks on the floor of the typical factory building.

Still another object of the present invention is to provide a conveyor system that is easy and inexpensive to maintain.

Still another object of the present invention is to pro.- vide an improved conveyor system that is substantially closed to the entry of foreign material into the chain slot.

A still further object of the present invention is to provide a conveyor system that may slidingly engage the tow pin at any point along the drive chain and guide the pin into proper driving engagement therewith.

Still another object of the present invention is to provide a conveyor system having an improved transfer mechanism.

Still another object of the present invention is to provide a transfer mechanism that is simpler, less expensive and easier to install than the systems heretofore known.

Another object of the present invention is to provide a conveyor system having a transfer mechanism that is smooth and reliable in operation.

Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a perspective view of a tow truck in towing engagement with. a conveyor system incorporating certain principles of the present invention;

FIGURE 2 is a plan view of a portion of the conveyor shown inFIGURE 1;

FIGURE 3 is a sectional view of FIGURE 2 taken alongline 33 thereof;

FIGURE 4 is a longitudinal, vertical sectional view taken on the line 44 of FIGURE 2;

FIGURE 5 is a transverse, vertical sectional view taken on the line 55 of FIGURE 2;

FIGURE 6 is a transverse, vertical sectional view taken on the line 66 of FIGURE 2;

FIGURE 7 is a plan view of a switch point in the conveyor system of this invention embodying and incorporating certain novel principles; and

FIGURE 8 is a longitudinal, vertical sectional view similar to FIGURE 4 but showing a modified form of the conveyor chain.

Referring now to the drawings, and particularly to FIGURE 1, there is illustrated a portion of a driven conveyor system 12 which is adapted to provide motive power to a tow truck 14 having a tow assembly 16 which includes a tow pin 18 mounted for vertical resilient reciprocable movement. The tow pin 18 is spring biased (not shown) in the downward direction to enable it to readily engage a conveyor chain 28 slidably received in a slot 22 (FIGURE 3) located below a pair of slot plates 24, 26. Thus, the tow truck 14 is pulled along a predetermined route 28 through the factory by means of the tow pin 18.

Often it is desired to route a laden tow truck to a particular assembly station or the like which is removed from the main track or way 28. In this situation, a system of branch paths, such as shown at 39 in FIGURE 7, must be provided to direct the truck 14 off the main path 28 and to free the main path 28 of these redirected tow trucks 14. In order to accomplish the transfer of the tow truck 14 to a branch path 38, it is necessary to release the tow pin 18 from the main conveyor chain 20. In the present system the tow pin 18 is released by lifting the pin 18 out of engagement with the chain by a release mechanism 32 which includes the tow assembly 16 and a cam 33 attached to the floor. After the pin 18 has been lifted,

a transfer mechanism 34 completes the transfer onto the branch track 38 as will be hereinafter described.

In order to actuate the transfer mechanism 34, the tow assembly 16 is equipped with a lift pin assembly 36 which operates to lift the tow pin 18 out of engagement with the conveyor chain 20 and allows its to be guided into the branch path 38. The lift pin assembly 36 comprises a pivot bar 38 which is adapted to pivot about an elongated pin 40 carried on a pair of angle irons 42. A pair of lifting channels 43 are suitably attached to and actuated by pivot bar 38, the channels 43 being adapted to engage a collar 44 fastened to tow pin 18. Thus, as pivot bar 38 is pivoted to actuate channels 43, the tow pin 18 is lifted by means of collar 44-.

The pivot bar 38 is also formed with a series of indexing apertures 48 adjustably carrying an indexing pin 50 which serves to pivot the bar 38 about the pin 40. The indexing pin 58 may be placed in any of the indexing apertures, 48 and is adapted to be engaged by the camming .surface 33 on the floor. It is to be understood that camming surfaces 33 may be placed in any transverse position to engage a pivot pin 50 placed in any of the nine indexing apertures 48 shown. Thus, with the proper selection of indexing apertures 48 to correspond to a series of camming surfaces 33 placed along the path of the conveyor system, a tow truck may be pre-programmed to follow any selected path through the system.

Attention is now directed to the details of the preferred embodiment of the straight section of the conveyor system illustrated in FIGURES 2 to 6. As was stated above, the system of the present invention is so fabricated and di mensioned as to allow the mounting thereof in the vertical space defined by the height of wooden blocks 60 which are overlaid on a concrete slab subfioor 62 conventionally found in manufacturing buildings or factories. When it is desired to install a conveyor system incorporating the principles of the present invention, a sufficient number of the wood blocks 60 are removed to accommodate the system which is suitably fastened to the concrete sub floor 62 beneath.

Specifically, a base plate 64 is fastened to the concrete subfloor 62 by a plurality of expansion bolts 66 or other types of anchoring devices. Mounted on the base plate 64, as by the same expansion bolts 66 or integrally formed therewith, are a pair of angle irons 68, 70 which form the sides of the race or way 22 which carries the conveyor 4.- chain 20 as defined above. A second pair of angle irons 72, 74 are supported on the vertical sides of angle irons 68, 70 respectively, and serve to form a mounting base for cover plates 78, 80. The cover plates 78, are fastened to the angle irons 68, 70 by flat-headed bolts 81 which are countersunk into plates 78, 80. In this way a smooth surface is obtained on the plates 78, 80 which is flush with the upper surface of the wood blocks 60.

The cover plates 78, 80 are relatively closely spaced at one edge thereof to define a slot 82 therebetween, and the other ends of the plates 78, 80 are butted by the wooden blocks 60. Thus, a relatively narrow opening to the race 22 is defined and is the only line of entry for any foreign material which may fall into the race 22. Itwill be seen as the description proceeds that this slot is effectively closed to the entry of foreign material by the particular configuration of the conveyor chain 20 which has been provided.

The conveyor chain 20, the details of which are best illustrated in FIGURES 2 to 5, generally comprises a plurality of upper links 86 which are vertically spaced from a plurality of lower links 88 by a pivotable connector 90. The connector 90 may take the form of a hardened steel rod 91 which has been press-fitted or journalled into apertures 92 formed in the outboard upper and lower links 86, 88. The inboard upper and lower links 86, 88 are pivotally mounted on pin 91 through apertures 94 which are received on a bushing 95 of hardened steel which has been journalled on pin 91.. Thus, the inboard links 86, 88 may pivot relative to the outboard links 86, 88 to provide a horizontal flexibility to the chain 20. This flexibility is exhibited in the fact that the chain 20 may traverse a curve having a radius in the order of five feet. Connector 90 is also adapted to rotatably support a horizontal roller 96 which serves to space the conveyor chain 20 in the race 22. To this end, suitable bearing material in the form of a bushing 98 is journalled on the bushing 95 to define a bearing race for the roller 96.

At the connector 90, the adjoining upper links 86 are lapped on each other with the leading link being offset downwardly to fall under the trailing link and the same general configuration is provided for the lower links 88. In referring to leading and trailing links, it is assumed that the chain is travelling from right to left in FIGURE 2. In conveyor chains of this type it is desired that the upper surfaces of the upper links 86 land the lower surfaces of the lower links 88 present substantially continuous or smooth surfaces for several reasons. First, as was stated above, the toW pin 18 is not placed into driving engagement with the chain 20 but rather is placed at any point thereon and the pin 18 slides on the upper surface of the upper links 86 until it is in alignment with a dog assembly 103. If the upper links 86 were merely overlapped without being offset, the probability of the tow pin :18 catching in the chain or bouncing over the dog assembly 103 is very great. Also, any irregularity in the surface .of the race 22 may catch chain 20 at the lower surface of lower links 88, thereby causing a slow-down or possibly a stoppage.

Thus, each link 86 is provided with offset portion 104 at the point where the adjacent links 86 are joined, thereby leaving a space 106 between the upper surfaces of adjacent links. This space 106 may be varied by varying the inclination of portion 104 to any degree consistent with the strength of the material. The distance 106 on FIGURE 4 is designed to be less than the diameter of the tow pin 18 to preventthe pin 18 from entering the space 106 between inclined surface 108 and edge 110 of the adjacent link. Assuming the chain to be traveling in the direction of the arrow, from right to left in FIGURES 2 and 4, the tow pin 18 will be seated over the edge 118 of the trailing link 86 before it leaves the upper surface of the leading link 86. Such a situation is illustrated in phantom on the left end of FIGURE 4.

The lower links 88 are similarly joined to avoid the stoppage of the chain from any obstruction that may be found in the race 22. The problem becomes more acute with the lower links 88 when it is necessary to drive the tow truck 14 either up or down an inclined surface as extraneous matter may accumulate at the juncture of the level surface with the inclined surface of the plate 64. In this regard, it is to be noted that the chain 20 is sufficiently flexible in the vertical direction as to traverse a vertical curve having a radius in the order of thirty feet.

Referring now to FIGURE 8, wherein there is illustrated a modified form of the link assembly described above, it is to be noted that the assembly of FIGURE 8 is identical to that of the other figures with the exception of that the overlapped portions of the links 86, 88 are reversed and the inclined surface 108 faces the direction of travel of the conveyor chain 20, viz. in the direction of the arrow. This modification further facilitates the passage of the tow pin 18 over the chain 20 in its search for dog assembly 103. In the modified form, any slight dipping of the end of the tow pin into the space between edge 110 and surface 108 will be taken care of by the camming action of surface 108. Thus, the system may be used with small tow pins 18, or slight irregularities may be tolerated.

In order to provide vertical support for the chain 20, alternate sets of upper and lower links 86, 88 are interrupted at the midpoints thereof and provided with a vertical roller assembly 112. The roller assembly 112 is adapted to travel on the base plate 64 when it is perfectly level and on either of the cover plates 78, 80 when the conveyor 12 is in a transversely inclined position depending on the direction of the inclination. The assembly 112 is fastened to leading link 86 by a pair of outer blocks 114 welded thereto and to the trailing link 86 by an inner block 116 which is also fastened by welding.

As shown in detail in FIGURES 2, 4 and 5, block 116 is formed with an upper vertical offset portion 118, the top of which is level with the upper surfaces of links 86 to maintain the uniform flat surface as described above. Similarly, the block 116 is formed with a lower offset portion 120 for a like reason with respect to the lower surface of links 88. The blocks 114, 116 are provided with horizontally aligned apertures 122 and 124 respectively, which receive an axle member to provide a horizontal pivot point for links 86, 88. Thus, chain 28 is able to traverse changes in elevation of race 22 without binding or jamming the chain 20. To decrease the wear on shaft member 130, a tubular bearing 132 of hardened steel material has been swedged on the shaft 130.

A pair of vertical roller assemblies 131, 132 are provided at either side of chain 20 for support thereof in the vertical direction and includes bearing races 134 and 136 which are press-fitted or otherwise attached to shaft member 130 and serve to form a rotatable mounting means for a pair of wheels 138. Suitable bearings, such as roller bearings 140, are disposed between bearing races 134, 136 and wheels 138 to reduce the friction therebetween. As is seen particularly in FIGURE 5, if the chain race 22 is transversely tilted in either direction, the wheels 138 are so positioned as to engage either base plate 64 or one or the other of cover plates 78 and 80. Thus, the danger of scraping chain 20 on the base plate 64 or cover plates 78, 80 is effectively eliminated.

Although not shown, it is to be understood that a suitable drive mechanism is contemplated for the system of the present invention. For example, a caterpillar drive of the type well known in the art may be supplied. In the present system, it is contemplated that the drive lugs on the caterpillar engage every other vertical roller 131, 132 to drive the chain. The outer vertical periphery of each vertical roller assembly 131, 132 has been provided with a recessed portion or pin pocket 139 which is adapted to be drivingly engaged by the lugs of the caterpillar drive system (not shown) described above.

A vertical roller assembly 140' is provided adjacent dog assembly 103 that is identical in every detail to that described above with the exception that a substantially solid center block 141 has been provided to accommodate a transversely elongated aperture or slot 148 therein. The leading portion of center block 141 is provided with a forward longitudinally extending tab 143 which is adapted to engage the pin 130 in a manner similar to that described in conjunction with roller assembly 112. The forward edge of tab 143 is provided with a forwardly and downwardly sloping surface 144 to provide a camming surface for the tow pin 18 to facilitate its traversal of the joint between tab 143 and link 86. Similarly, an inclined surface 145 is provided on the tab 143 to preclude chain 20 catching on any irregularity in the bottom of race 22.

As described above, the spring biased tow pin 18 is merely dropped into slot 82 and allowed to slide along the upper surface of links 86 as the chain travels in race 22. The pin slides down inclined surface 149 and continues to slide on center block 141 until it positions itself over slot 148. The pin 18 then abuts the combination of a diverter link 150 and spacer member 152 which have been welded to bar 141 upstream of aperture 148, thereby stopping further travel on chain 20. Thus, the chain 20 engages tow bar 18 and the spring therein positions the tow bar 18 in slot 148. It is to be noted that pin 18 is limited in its downward travel by channel irons 43 described in conjunction with FIGURE 1 so that the smooth surface formed by block 141 and lower link 88 remains unbroken. With this engagement, the tow truck 14 will travel along the system in a path defined by the path of conveyor chain 20.

Referring back to FIGURES l, 3, 5 and 6, particular attention is directed to the particular relation between the upper links 86 of the conveyor chain 28 and the slot 82 provided between cover plates 78 and 88. As was described above, many conveyor systems of the prior art are substantially open at the top, allowing dirt, assembly parts and the like to fall into the chain race, thus binding or stopping the travel of the chain. Certain conveyor systems of the prior art have attempted to obviate this problem by forming the upper link of the chain in such a manner as to have the upper link ride on the cover plates or upper surface of the race forming channel irons and thus suspend the rest of the chain therefrom. While a conveyor chain of this type is suitable for use in a system of a factory, there are certain inherent disadvantages thereto. For example, a substantially larger amount of power is required to drive such a system over that of the roller type proposed by applicant due to the larger friction forces present between the upper link and the supporting member. Also, the upper link projecting above the floor line presents a problem due to the uneven surface made with the floor. Thus, rolling vehicles and workers crossing the system may have difficulties due to the projection of the upper link.

The system of the instant invention is so designed to effectively close the tow bar slot 82 without the problems of the prior art outlined above. As is seen from the drawings, each element of the upper portion of the conveyor chain is formed sufiiciently wide as to extend beyond the transverse dimension of the tow pin slot 82. Therefore, any assembly line material, tools, fasteners and the like which may have a tendency to fall into the race 22 are effectively stopped by the upper link 86 of the chain 20. Thus, the race 22 may be kept free of foreign material which may have a tendency to bind or stop the free movement of the chain 20.

Referring back to FIGURE 2, the diverter link 150 is formed with a pair of camming surfaces 156, 158 which serve to divert tow pin 18 either right or left, respectively, as will be hereinafter explained with reference to FIG- URES l and 7. As was stated in conjunction with FIG- URE 1, index pin 58 is adapted to engage camniing surface 33, thus pivoting bar 38 about rod 48. The pair of lifting channels 43 are fixed to 'bar 38 and actuated up- '7 wardly thereby. The lifting channels engage a collar portion 44 to pivot and thereby lift the end of tow pin 18 from its lowermost position.

As tow pin 18 approaches a branch way 30, to which it is desired that the pin 18 be switched, it is necessary to lift the pin 18 out of engagement with aperture 148 by the above-described method and divert the pin 18 to the branch path 30. It is important to note that the pin 18 is lifted only to a height sufiicient to disengage it from the aperture 148 but not high enough to clear diverter link 150.

Referring particularly to FIGURE 7, as the pin 13 enters the switching section and prior to the lifting thereof, the pin 18 is engaged by an angled surface 168 of a protrusion 170 formed on cover plate 80. In this manner, the pin 18 is guided to the right extremity of elongated aperture 148, corresponding to the direction of the branch way 38. At the time when the pin 18 is engaging a flat surface 172, it is lifted as described above and freed from aperture 148. The pin 13 then slides rearwardly on the upper surface of block 141 until it engages camming surface 156. The pin 18 is then urged outwardly by surface 156 until such time as the lower portion of pin 18 enters a vertical slot 173 formed in channel iron 68, which position also corresponds to the clearance of a projection 176 on cover plate 78 on the downstream side of the switching section. It is to be noted that the transverse dimension of diverter plate 159 is sufiicient to extend into branch way 30 a sufficient distance that the pin 18 clears the projection 176.

If it is desired that two truck 14 remain on the main way 28, then the indexing pin 59 is omitted or so positioned that it will not engage camming surface 33. Thus, the tow pin 18 will not be lifted and will merely be moved to the right side of aperture 148. In this situation, the tow pin 18 will engage a further camming surface 178 formed at the inner edge of cover plate 78 downstream from the switching section. The effect will be to return the two pin 18 to its median position in aperture 148 and cover plates 78, 39 will maintain this position.

It is to be understood that the tow pin 18 may be diverted to a branch way to the left of main way 28. In this case the camming surfaces 168, .178 are reversed and the opposite camming surface 158 of diverter plate 15% is used. On reaching the branch way 3t), a further power driven chain may be provided to clear the tow truck from the main line. Thus, a complete system of chain conveyor has been described that serves to accomplish the movement of goods in a factory in a manner not heretofore known.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

I claim:

1. A conveyor chain assembly adapted to be installed in a chain race defined by a pair of spaced side members, means forming a base portion and a pair of spaced cover plate members supported thereby, the cover plate members defining a slot adapted to receive a tow pin of a truck, said chain assembly comprising:

a plurality of upper links joined together. and formed to present a smooth upper surface closely adjacent and below the slot,

a plurality of interconnected lower links spaced below said upper links and parallel thereto,

connector means for joining said upper and lower links,

first means carried by said upper and lower links for spacing said chain from the side walls, and

second means carried by said upper and lower links for vertically supporting said chain,

said upper links being further formed to transversely underlap each of the cover plates for providing a vertical closure for the slot.

2. A conveyor chain assembly adapted to be installed in a chain race defined by a pair of spaced side members, means forming a base portion and a pair of spaced cover plate members supported thereby, the cover plate mem- 5 bers defining a slot adapted to receive a tow pin of a truck, said chain assembly comprising:

a plurality of upper links joined together to form a continuous line of links,

at least certain of said links having an offset portion lapping an adjacent link for providing a smooth up per suiface closely adjacent and below the slot,

a plurality of interconnected lower links spaced below said upper links and parallel thereto,

connector means for joining said upper and lower links,

first means carried by said upper and lower links for spacing said chain from the side walls, and

second means carried by said upper and lower links for vertically supporting said chain,

said upper links being further formed to transversely underlap each of the cover plates for providing a vertical closure for the slot.

3. A conveyor chain assembly adapted to be installed in a chain race defined by a pair of spaced side members, means forming a base portion and a pair of spaced cover plate members supported thereby, the cover plate members defining a slot adapted to receive a tow pin of a truck, said chain assembly comprising:

a plurality of upper links joined together to form a continuous line of links,

each of said upper links having an oifset portion lapping an adjacent link for providing a smooth upper surface closely adjacent and below the slot,

a plurality of interconnected lower links spaced below said upper links and parallel thereto,

connector means for joining said upper and lower links,

first means carried by said upper and lower links for spacing said chain from the side walls, and

second means carried by said upper and lower links for vertically supporting said chain,

said upper links being further formed to transversely underlap each of the cover plates for providing a vertical closure for the slot.

4. A conveyor chain assembly adapted to be installed in a chain race defined by a pair of spaced side members, imeans forming a base portion and a pair of spaced cover plate members supported thereby, the cover plate members defining a slot adapted to receive a tow pin of a truck, said chain assembly comprising:

a plurality of upper links having a straight portion and an offset port-ion,

said upper links being joined together so that said straight portion of one of said links laps said offset portion of an adjacent one of said links for providing a smooth upper surface closely adjacent and below the slot,

a plurality of lower links spaced below said upper links and joined together to form a smooth lower surface parallel to said upper surface,

copnector means for joining said upper and lower inks,

first means carried by said upper and lower links for spacing said chain from the side walls, and

second means carried by said upper and lower links for vertically supporting said chain,

said upper links being further formed to transversely underlap each of the cover plates for providing a vertical closure for the slot.

5. A conveyor chain assembly for use in a race and with a load carrying vehicle having tow means mounted 70 thereon adapted to operatively engage said chain for providing motive power to said vehicle comprising:

a plurality of upper links having upper surfaces thereon and pivotally connected together so that said surfaces are in aligned relation to form a continuous line of 75 links,

a plurality of lower links pivotally connected together to form a continuous line of links and spaced parallel to said upper links,

connector means interconnecting said upper and lower links,

first friction reducing means carried on said connector means for horizontally spacing said chain in the race,

second friction reducing means supported by at least one of said upper and lower links for vertically supporting said chain in the race, and

a dog assembly disposed adjacent said upper links and adapted to drivingly engage the tow means,

said upper links being formed and interconnected so that the tow means engages a substantially smooth and continuous surface when in engagement with said upper links.

6. A conveyor chain assembly for use in a race and with a load carrying vehicle having tow means mounted thereon adapted to operatively engage said chain for providing motive power to said vehicle comprising:

a plurality of upper links having upper surfaces thereon and joined together to form a continuous line of links,

at least certain of said links having an oflfset portion lapping an adjacent link for providing said upper surface with a smooth and substantially unbroken profile, closely adjacent and below the slot,

a plurality of lower links pivotally connected together to form a continuous line of links and spaced parallel to said upper links,

connector means interconnecting said upper and lower lin'ks,

first, friction reducing means carried on said connector means for horizontally spacing said chain in the race,

second friction reducing means supported by at least one of said upper and lower links for vertically supporting said chain in the race, and

a dog assembly disposed adjacent said upper links and adapted to drivingly engage the tow means,

said upper links being formed and interconnected so that the tow means engages a substantially smooth and continuous surface when in engagement with said upper links.

7. A conveyor chain assembly for use in a race and with a load carrying vehicle having tow means mounted thereon adapted to operatively engage said chain for providing motive power to said vehicle comprising:

a plurality of upper links having upper surfaces thereon and joined together to form a continuous line of links,

each of said upper links having an olfset portion lapping an adjacent link for providing said upper surface with a smooth and substantially unbroken profile closely adjacent and below the slot,

a plurality of lowerlinks pivotally connected together to form a continuous line of links and spaced parallel to said upper links,

connector means interconnecting said upper and lower links,

first friction reducing means carried on said connector means for horizontally spacing said chain in the race,

second friction reducing means supported by at least one of said upper and lower links for vertically supporting said chain in the race, and

a dog assembly disposed adjacent said upper links and adapted to drivingly engage the tow means,

said upper links being formed and interconnected so that the tow means engages a substantially smooth and continuous surface when in engagement with said upper links.

8. A conveyor chain assembly for use in a race and with a load carrying vehicle having tow means mounted thereon adapted to operatively engage said chain for providing motive power to said vehicle comprising:

a plurality of upper links having a straight portion and an offset portion and joined together to form a continuous line of links,

said upper links being joined together so that said straight portion of one of said links laps said offset portion of an adjacent one of said links for providing a smooth upper surface closely adjacent and below the slot,

a plurality of lower links spaced below and parallel to said upper links and joined together to form a smooth lower surface parallel to said upper surface,

connector means interconnecting said upper and lower links,

first friction reducing means carried on said connector means for horizontally spacing said chain in the race,

second friction reducing means supported by at least one of said upper and lower links for vertically supporting said chain in the race, and

a dog assembly disposed adjacent said upper links and adapted to drivingly engage the tow means,

said upper links being formed and interconnected so that the tow means engages a substantially smooth and continuous surface when in engagement with said upper links.

9. A conveyor chain assembly for use in a race and with a load carrying vehicle having tow means mounted thereon adapted to operatively engage said chain for providing motive power to said vehicle comprising:

a plurality of upper links having a straight portion and an offset portion and joined together to form a continuous line of links,

said upper links being joined together so that said straight portion of one of said links laps said ofiset portion of an adjacent one of said links for providing a smooth upper surface closely adjacent and below the slot,

a plurality of lower links spaced below and parallel to said upper links and joined together to form a smooth lower surface parallel to said upper surface,

connector means interconnecting said upper and lower links,

first friction reducing means carried on said connector means for horizontally spacing said chain in the race,

second friction reducing means supported by at least one of said upper and lower links for vertically supporting said chain in the race, and

a dog assembly disposed in line with said upper links having an aperture formed therein between lines formed by said smooth upper surface and said smooth lower surface and adapted to drivingly engage the tow means when the tow means leaves said upper surface,

said upper links being formed and interconnected so that the tow means engages a substantially smooth and continuous surface when in engagement with said upper links.

10. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture,

said diverter link having at least one surface thereon inclined to the elongation axis of said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means.

11. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture,

said diverter link having at least one surface thereon inclined to the elongation axis of said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means,

said diverter link being of sufficient transverse dimension as to partially extend said inclined surface into the branch path.

12. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising-the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced downstream of said aperture having means spaced immediately adjacent said aperture :for abutting the tow means when the tow means is positioned above said aperture,

said diverter link having at least one surface thereon inclined to the elongation axis of said aperture for engaging and diverting the tow means intothe branch path when the tow means is raised by the lifting means.

13. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced downstream of said aperture having means spaced immediately adjacent said aperture for abutting the tow means when the tow means is positioned above said aperture,

said diverter link having at least one surface thereon inclined to the elongation axis of said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means,

said diverter link being of sufficient transverse dimension as to partially extend said inclined surface into the branch path.

14. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture,

said diverter link having a substantially vertical surface thereon inclined outwardly in the direction of the branch path and upstream from said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means.

15. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprisin a plurality of upper and lower links, interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links, an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link'supported by said body member spaced upstream of said aperture,

said diverter link having a substantially vertical surface thereon inclined outwardly in .the direction of the branch path'and upstream from said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means,

said diverter link being of sufiicient transverse dimen- :13 sion as to partially extend said inclined surface into the branch path.

16. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith an operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture having means spaced immediately adjacent said aperture for abutting the tow means when the tow means is positioned above said aperture,

said diverter link having a substantially vertical surface thereon inclined outwardly in the direction of the branch path and upstream from said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means.

'17. A conveyor chain adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, the intersection having lifting means associated therewith for raising the tow means and further means for urging the tow pin towards the branch path, said chain comprising:

a plurality of upper and lower links interconnected to form a chain, and

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture having means spaced immediately adjacent said aperture for abutting the tow means when the tow means is positioned above said aperture,

said diverter link having a substantially vertical surface thereon inclined outwardly in the direction of the branch path and upstream from said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means,

said diverter link being of sufficient transverse dimension as to partially extend said inclined surface into the branch path.

18. A conveyor system adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, said system comprising:

a race formed by a base member and a plurality of side members,

a plurality of upper and lower links interconnected to form a chain carried in said race for drivingly engaging the tow means,

a plurality of cover plates supported over said race and separated to form a slot receiving the tow means, at least one of said cover plates having a portion thereon extending into said slot adjacent the branch path for urging the tow means toward the branch path,

a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture,

said diverter link having at least one surface thereon inclined to the elongation axis of said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means,

said diverter link being of suflicient transverse dimension as to partially extend said inclined surface into the branch path.

19. A conveyor system adapted for use in a race having a main path and at least one branch path intersecting therewith and operative to provide motive power to a load bearing vehicle having a raisable tow means mounted thereon, said system comprising:

a race formed by a base member and a plurality of side members,

a plurality of upper and lower links interconnected to form a chain carried in said race for drivingly engaging the tow means,

a plurality of cover plates supported over said race and separated to form a slot receiving the tow means,

at least one of said cover plates having a portion thereon extending into said slot adjacent the branch path for urging the tow means toward the branch path, a dog assembly disposed within said chain and adapted to drivingly engage the tow means for providing motive power to the vehicle, said dog assembly having a body member connected to said links,

an aperture formed in said body member having an axis of elongation transverse to said chain and adapted to positively engage the tow means when the tow means is in driving engagement with said chain, and

a diverter link supported by said body member spaced upstream of said aperture,

said diverter link having at least one surface thereon inclined to the elongation axis of said aperture for engaging and diverting the tow means into the branch path when the tow means is raised by the lifting means,

said diverter link being of sufiicient transverse dimension as to partially extend said inclined surface into the branch path.

References Cited by the Examiner UNITED STATES PATENTS 2,689,036 9/1954 Mullen et al 104-l72 X 2,936,718 5/1960 Bradt et a1 l04-172 3,103,896 9/1963 Zebley et al. 104-173 3,160,115 12/1964 Bradt et a1 104-172 ARTHUR L. LA POINT, Primary Examiner.

F. W. MONAGHAN, S. T. KRAWCZEWICZ,

Assistant Examiners. 

1. A CONVEYOR CHAIN ASSEMBLY ADAPTED TO BE INSTALLED IN A CHAIN RACE DEFINED BY A PAIR OF SPACED COVER MEANS FORMING A BASE PORTION AND A PAIR OF SPACED COVER PLATE MEMBERS SUPPORTED THEREBY, THE COVER PLATE MEMBERS DEFINING A SLOT ADAPTED TO RECEIVE A TOW PIN OF A TRUCK, SAID CHAIN ASSEMBLY COMPRISING: A PLURALITY OF UPPER LINKS JOINED TOGETHER AND FORMED TO PRESENT A SMOOTH UPPER SURFACE CLOSELY ADJACENT AND BELOW THE SLOT, A PLURALITY OF INTERCONNECTED LOWER LINKS SPACED BELOW SAID UPPER LINKS AND PARALLEL THERETO, CONNECTOR MEANS FOR JOINING SAID UPPER AND LOWER LINKS FIRST MEANS CARRIED BY SAID UPPER AND LOWER LINKS FOR SPACING SAID CHAIN FROM THE SIDE WALLS, AND SECOND MEANS CARRIED BY SAID UPPER AND LOWER LINKS FOR VERTICALLY SUPPORTING SAID CHAIN, SAID UPPER LINKS BEING FURTHER FORMED TO TRANSVERSELY UNDERLAP EACH OF THE COVER PLATES FOR PROVIDING A VERTICAL CLOSURE FOR THE SLOT. 